LLVM: fixed a small problem on Windows when in debug mode (related to issue #913).
LLVM: fixed a small problem on Windows when in debug mode (related to issue #913).

Finally found the cause (and fix) of the problem that resulted in the
debug version of OpenCOR crashing when switching to the Single Cell
view. FWIW, the message was:

Program: C:\Users\Alan\Desktop\OpenCOR\build\MSVCP120D.dll
File: C:\Program Files (x86)\Microsoft Visual Studio
12.0\VC\INCLUDE\xutility
Line: 2796

Expression: invalid null pointer

mirams/opencor,mirams/opencor,mirams/opencor,mirams/opencor,mirams/opencor